1. Field of the Invention
The present invention relates to an excess flow shut off device which prevents water from spouting out by automatically blocking an outlet when a water supply hose is cut or damaged.
2. Background Art
FIG. 1 illustrates U.S. Patent Laid-open No. 2011-0232779 entitled “an excess flow safety shut-off device” which has been filed by the inventor of the present invention. The excess flow safety shut-off device has a structure that a ball 2 blocks an outlet 3 when a hose is damaged so as to occur a fluid flow exceeding a magnetic force of a magnet 1.
However, such an excess flow safety shut-off device according to the prior art has a problem in that there frequently occurs a malfunction that the ball 2 blocks the outlet 3 even in a state where the hose is not damaged because the shut-off device reacts sensitively to the fluid flow.
Moreover, U.S. Pat. No. 4,830,046 discloses an excess flow control valve for blocking an opening and closing member, which is supported by a spring, when there is an abnormal flow of a fluid. However, in case of such shut-off devices including the above-mentioned excess flow control valve, it is difficult to set the opening and closing member to overcome an elastic force of the spring under predetermined conditions because their components are separately manufactured and managed.
For the above reason, the shut-off devices according to the prior arts have a problem in that people avoid using the shut-off devices in spite of usefulness because the shut-off devices are not operated even though the shut-off valve is operated in a normal state or the hose is cut.
Taking a notice that the above-mentioned problem of the excess flow shut-off devices of the prior arts happens because components are not modulated properly for quality management, the inventor created this invention.